My mower will only start when i spry wd 40 on the blade assembly

yes you can use wd-40 and spry it all over the spring

The tight spot that you are noticing is the compression stroke of the engine. The blade is hooked to the crank shaft, which also means that if you are spinning it by hand and still have the spark plug hooked up to the plug wire, you could potentially start the mower and chop your hand to bits. WD-40 will not free anything up here and the stiff spot you feel is not a problem. Be safe out there.

The mower's drive shaft may need to be lubricated. If you turn the mower over and try to move the blade by hand (with the mower off, of course) does it move, or is it hard to move? If it's hard to move or it won't move at all, lubricate the shaft by squirting some WD-40, 3-In-1, or other lubricating oil onto the drive shaft where it meets the chassis of the mower. Squirt enough oil to cover the circumference of the drive shaft, then try to spin the blade again. It should at least spin a little bit now. Squirt some more oil and spin the blade again, until the blade spins easily. Then turn the mower back over and try to pull the start cord -- it should pull normally now.

Remove and clean then replace the entire assembly that tightens the belt when you engage the blade.It should have a spring clean the spring with WD-40.This will allow it to release completely,and not spin the blades.

You probably have grass or other debris caught up on the drive shaft. Turn the mower over, and where the drive shaft (that the blade rides on) disappears into the mower, squirt some WD-40. Make sure to go around the circumference of the shaft.

Then turn the blade by hand (carefully -- you might want to wear thick gloves) and apply some more WD-40. The blade should become easier to turn, which will allow your pull cord to be pulled all the way out.

If the cord pulls farther than it did before but still not far enough, repeat the procedure and apply more WD-40 or oil.

The drive shaft might just need to be oiled. Turn the mower over and locate the drive shaft, where it goes from the mower's blade up into the body of the mower. Lubricate the area of the shaft that disappears into the body with WD-40 or another lubricant, then turn the blade by hand (be careful!) and squirt some more oil.

Eventually the blade should become easier to turn, and then your pull cord should extend without getting stuck. Good luck!

sound like timing is off sherd a key in flywheel
take cover off where you pull the rope and then
take off nut off flywheel its going to be tight and hard to get off but can be done take a screwdriver to hold flywheel ones the nut off look around shaft see if flywheel key is sherd
or pry off flywheel be carefull dont damage anything if sherd replace key

use piece of wood to block blade. Then spay wd-40 or a can of penatrating oil on blade . Then try to remove bolt. Otherwise I recommend heating up bolt with torch and then it should come off.

There is a idler pivot plate on the mower that must be cleaned and lubricated regularly, from the left side of the mower deck if you look in the middle of the mower deck while someone engages the mower(with the engine off) you will see the pulley try and move,there is a 3/8 bolt that comes up through a bushing that this pivots on, soak that area with wd-40 and see if that improves the movement. Be sure not to get any wd-40 on the belt or pulleys. Always try and keep that area clean and lubed.

check the wire at the clutch on the crank shaft end try spraying the clutch with P B spry